The following sleeping pads are suitable for hiking. Some are less than 500g.  Others weigh  bit more with a bit more comfort factor.  Choosing a mat is a matter of real personal choice. See pillows & sleeping bags.
The lightest full-length pad is the Klymit Inertia X Frame at 258 g but a more practical one for mild Australian conditions might be the Exped AirMat Basic Ultralight 7.5 Medium at 355g.

Big Agnes AXLMummy 272 g
Insulated Mummy 369g
Rectangle 269g
Blackwolf Hexatherm Lite Hiker520g
EPE Global 3/4 Size Core Liteepe_global_34Length Long 183cm, Standard 122cm
Width 51cm
Thickness 2.5cm
Weight Long 820g, Standard 540gDimensions: 122 x 51 x 2.5cm
Packed Stuff bag dimensions (approx): 25 x 12cm
Weight: approx 400 grams
Exped AirMat Basic Ultralight 7.5 Mediumexped_airmat_basicSize 182 x 50 cm
Thickness 7.5 cm
Weight 355g
Packed 21×7.5
Min Temp 11
Exped Down MatExped have a large range of sleeping mats.  If you are looking for more luxury, good weight and huge R value check out the Exped Down range.
DownMat 7Pump Short: 120x52x7 cm 640 g / 22.6 oz Packed: 23×12 cm R-value 5.9
DownMat 7 Pump: 183x52x7 cm 880 g / 31 oz Packed: 23×16 cm R-value: 5.9
DownMat 7Pump DLX: 197x65x7 cm 1150 g / 40.6 oz Packed: 27×14 cm R-value: 5.9
DownMat 9 Pump: 183x52x9 cm 990 g / 34.9 oz Packed: 24×16 cm R-value: 8
DownMat 9 Pump DLX: 197x65x9 cm 1270 g / 44.8 oz Packed: 27×16 cm R-value: 8
Review | Review | Review
Exped Sim Lightexped_simThe Sim Light range is for the minimalist.
SIM Light 2.5 Short: Size: 120x50x2.5 cm Weight: 430g /15 oz Packed: 19×12 cm / 7×5“
SIM Light 2.5 Mummy: Size: 183x50x2.5 cm Weight: 610g /22 oz Packed: 20×15 cm / 8×6“
SIM Light 2.5: Size: 183x50x2.5 cm Weight: 640g /23 oz Packed: 20×15 cm / 8×6“
SIM 2.5: Size: 183x50x2.5 cm Weight: 790g /27.9 oz Packed: 20×16 cm / 8×6“
SIM Light 3.8: Size: 183x50x3.8 cm Weight: 760g /27 oz Packed: 27×16 cm / 11×6“
SIM Light 3.8 DLX: Size: 197x65x3.8 cm Weight: 1060g /37 oz Packed: 33×17 cm / 13×7“
Review | Review
Gossamer Gear NightLight™ Sleeping Padgossamer_NightLight_FullWeight:
varies 12 to 12.4 oz. (340 – 352 g.)
Size:
19 x 76 x 3/4 in. (48 x 193 x 2 cm.)
Pad rolls to 8 in. (20 cm.) diameter by 19 in. (48 cm.) long
note: Sizes may vary up to + or – 1/2 in. (1.3 cm.)
Materials:
Closed Cell Cross Linked EVA Polyolefin FoamReview | Review
Highlander EVA Foam Matshighlander_compact_matCompact 140x50x0.8cm   Weight:  0.14 kg
Camper 180x50x0.8cm Weight: 0.18 kg
Explore 180x50x1cm Weight: 0.47 kg
Highlander Aluminium Foil Mathighlander_foil_matThermally reflective and insulating
Water-resistantItem Dimension: 180x60x0.2cm
Weight: 0.12 kg
Highlander inflatable sleeping mat with pumphighlander_inflatableFabric/Materials: PU coated PVC
Item Dimension: 180x50x7cm
Pack Size: 12×8.5x25cm
Weight: 0.84 kg
Karrimorkarrimor_matLength 185cm
Width 51cm
Thickness  2.5cm.
Weight 680 gram
Kathmandu v225kathmandu_v225Length Long 183cm, Standard 120cm
Width 51cm
Thickness 2.5cm
Weight Long 820g, Standard 540g
Kathmandu V238kathmandu_v238Length Long 183cm, Standard 120cm
Width 51cm
Thickness 3.8cm
Weight Long 1120g, Standard 740gThe more recent range which became available post-August 2010 is called the Compact Lite with stats as follows:
Weight Long 890g, Standard 595g
and the Self Inflating Mat Hike 38
Weight Long 1,000g, Standard 640g
Klymit Inertia X Frameklymit_inertia1World’s lightest full length pad at 9.1 ounces 260g
Metzeler Thermo Air Light Long & 3/4metzeler_34German made
Length Long 191 cm, 3/4 121 cm
Width: 61 cm
Thickness 3.0 cm
Weight 1050 grams, 3/4 650 grams
Size in bag: 17 cm diameter x 33 cm (Folds in half then rolls up)
Mountain Designs Airlite 5.5R-Value 3.3
Packed Dimensions 28cm L x 11cm W x 11cm H
Dimensions Inflated: 185cm L x 55cm W x 5.5cm H
Packed: 28cm L x 11cm W x 11cm H
Mat Weight: 0.60kg
Pump Sack Weight: 0.09kg
Total Weight: 0.69kg
Nemo TensorMinimum Weight 1 lb , 1 oz / 475 g
Packed Weight 1 lb , 4 oz / 555 g
Packed Size 8.0 x 3.0 in dia / 20 x 8 cm dia
Climate Extreme Cold
R-Value 4.8
Thickness 3.0 in
Dimensions 72 x 20 x 3.0 in / 183 x 51 x 8 cm
Shape Mummy
Nemo Astro (warm and comfort) RegularMinimum Weight: 1 lb , 8 oz / 690 g
Packed Weight: 1 lb , 10 oz / 730 g
Packed Size: 8.5 x 4.5 in dia / 22 x 11 cm dia
Temp Rating: 15 to 25F / -9 to -4C
Thickness: 3.5 in
Dimensions: 72 x 20 x 3.5 in / 183 x 51 x 9 cm
Shape: Rectangular
Color: Dark Verglas
Insulation: PrimaLoft®
Fabric: 75D PU Polyester
Nunatak LunanunapadThe Luna Pad measures 19.5″ x 78″
and rolls up to a diameter of about 12″.Using our ultra sensitive electronic down scale we measured the pad to weigh an incredible 12 oz.
The Luna Pad has an overall thickness of 3/4″, with the foam in the ‘valleys’ a little more than quarter of an inch thick.
Color is a neutral light gray.
12 ounces,  340g
Outerlimits 3/4outerlimits_34
Ozmate full  & 3/4ozmate_34Length Long 183, 3/4 122cm
Width 51 cm
Thickness  25 mm
Weight 850 g, 3/4 500 g
Packed size 3/4 25cm x 13cm
Pacific Outdoor Peak Oyl litePacific_Outdoor _Peak_Oyl_LiteLength Long 198 cm, Regular 183cm, 2/3 122cm
Width 51 cm
Thickness  25 mm
Weight Long 585 g, Regular 539 g, 2/3 360 g
Review | Review
See To Summit Ultralight Sleeping Mat LargeSize Variation: Large
Length: 78 in/198 cm
Width: 25 in/64 cm
Height/Depth: 2 in/5 cm
Weight: 17.5 oz/495g
Packed Size: 3 X 8 in/7.5 x 20cm
R Value: 0.7
Thermarest Neoair XLitethermarest_40th_anniversarySize: Regular
Weight (Standard): 12 oz
Weight (Metric): 0.34 kg
Width (Standard): 20 in 25 in
Width (Metric): 51 cm
Length (Standard): 72 in
Length (Metric): 183 cm
Packed dimension (Standard): 9 in x 4.1 in
Packed dimension (Metric): 23 cm x 10 cm
Vango Ultralite Full & 3/4vango_ultralite_343/4 Dimensions 120 x 51 x 2.5cm
Weight 430g (460g with stuffsac)
Pack size 32 x 14cmFull Dimensions 183 x 51 x 2.5cm
Weight 650g (710g with stuffsac)
Pack size 33 x 16cm