Damien Martyn scored an unbeaten 104 as Australia reached 320 for five in their second innings before torrential rain washed out the third afternoon of the second Test against Sri Lanka on Thursday.

Australia, resuming on 211 for two after conceding a 91-run first-innings deficit, extended their overall lead to 229 before play ended 46 overs early.

Martyn, dropped on 65, batted defensively for a marathon seventh Test hundred that spanned 397 minutes and 274 balls and included 14 boundaries.

It was his second consecutive century in the series, further repaying the selectors faith in him despite a lean 25-month spell without a three-figure score.

His watchful innings frustrated off spinner Muttiah Muralitharan, who ended the day with one for 126, his only success the wicket of Adam Gilchrist for 144.

All-rounder Andrew Symonds was unbeaten on six after a difficult 52 minutes at the crease when bad light and rain interrupted play halfway through the afternoon.

Left-arm seamer Chaminda Vaas was Sri Lanka's most successful bowler, taking three for 78 from 24 hardworking overs.

Muralitharan trapped Gilchrist leg before wicket in the fourth over of the day to end a 200-run partnership for the third wicket.

Gilchrist, promoted to number three after Ricky Ponting injured his back, faced 185 balls and hit 19 fours and three sixes.

Lehmann played positively, hitting four boundaries in his 21, before Chaminda Vaas trapped him leg before wicket with an inswinger in his second over of the day to leave Australia 255 for four.

Ponting (27), who was able to bat after an intensive 24 hours of physiotherapy, added 49 in 113 balls with Martyn for the fifth wicket.

Sri Lanka took the new ball in the 88th over of the innings and broke through after lunch when umpire Dave Orchard gave Ponting out caught behind, although the ball appeared to flick his pad.

Australia lead the series 1-0 after their 197-run victory in Galle last week.

Scoreboard:

Australia first innings: 120 all out

Sri Lanka first innings: 211 all out

Australia second innings (overnight 221-2)
J.Langer c Sangakkara b Zoysa 9
M.Hayden c & b Vaas 5
A.Gilchrist lbw Muralitharan 144
D.Martyn not out 104
D.Lehmann lbw b Vaas 21
R.Ponting c Sangakkara b Vaas 27
A.Symonds not out 6

Extras (lb-3 nb-1) 4

Total (for five wickets, 103 overs) 320

Fall of wickets: 1-11, 2-26, 3-226, 4-255, 5-304.

To bat: S.Warne, J.Gillespie, M.Kasprowicz, S.MacGill.

Bowling: Vaas 24-5-78-3 (1-nb), Muralitharan 38-7-126-1, Zoysa 23-9-58-1, Lokuarachchi 12-2-33-0, Jayasuriya 5-0-16-0, Dilshan 1-0-6-0.