He will meet Black Jack Shannon McIlroy (Nelson) in this morning's men's singles final at the Burnside green.
Girdler (51) came back into international bowls in convincing style last month when he won gold medals in the triples and fours at the Asia and Pacific championships at Christchurch.
He had been in the wilderness for 11 years after playing his 192nd international for the Black Jacks in 2004.
In the quarterfinals he outplayed Gary Lawson (Eastbourne) 21-9.
In the semifinals Girdler won a close tussle against current Black Jack Ali Forsyth (Nelson) 21-19, with a ferocious drive to the ditch that brought him three points when Forsyth had two shots on the head.
Forsyth has won three singles titles.
Girdler is the bowls co-ordinator at the Tweed Head Club in New South Wales and has hardened his game in the tough Australian competition.
McIlroy reached the final when he beat defending champion Mike Kernaghan (North East Valley) 21-14.
In the quarterfinals he beat another Otago bowler Evan Roberts (North East Valley) 21-9.
In the men's pairs Kernaghan and Black Jack Tony Grantham ((Auckland) were beaten in the first post-section round by former Dunedin bowlers Kevin Gore and Ross Stevens (Canterbury) 14-10.
Alistair Waugh and Peter Andres (Taieri) were beaten in the second round and Ken Walker (Taieri) and Phil Ashton (Palmerston North) lost to semifinalists Andrew Howie and Greg Dale (Australia) 19-9 in the third round.
Defending champions Rob Ashton and Peter Sain (Carlton Cornwall) edged out Gary Lawson and McIlroy 19-18.
Because of heavy rain in Christchurch, only one round of the men's and women's pairs were played yesterday.
The pairs semifinals will be played this morning and the finals in the afternoon.
Two Otago women's teams reached the quarterfinals of the pairs.
Sarah Scott (North East Valley) and Bronwyn Stevens (Southland) were beaten 19-18 on the extra end by 2008 world champions Jo Edwards and Val Smith (Nelson).
The Central Otago pair of Margaret O'Connor (Queenstown) and Linley O'Callaghan (Alexandra) lost to the Mid-Canterbury pair of Sandra Keith and Serena Matthews, who won the 2013 title, 21-12.
But they had the satisfaction of knocking out the Australian pair of Kelsey Cottrell and Marilyn Clayton 16-15 in the second round.
Cottrell won gold medals in the pairs and fours at the Asia and Pacific Games last month.
The other semifinalists are sisters and defending champions Mandy and Angela Boyd and last year's singles champion Leigh Griffin and her daughter Kirsten (Victoria).
Cottrell will meet promising Canterbury bowler Tayla Bruce (Burnside) in the women's singles final. Bruce was runner-up in Dunedin two years ago.
NZ Championships
in Christchurch
Singles finalists: Kelsey Cottrell (Australia) v Tayla Bruce (Canterbury).
Paul Girdler (Tweed Heads) v Shannon McIlroy (Nelson).
Start times: Singles (10.45pm) at Burnside green; pairs: semifinals 8.15am and finals 1.30pm.
