(Adds election board decision on Yalova province)
ANKARA, April 9 (Reuters) - Turkey's opposition failed on Thursday to have the results of a local election in Ankara cancelled in an attempt to salvage some victory from nationwide polls that proved a triumph for Prime Minister Tayyip Erdogan.
Turkey's High Election Board refused an appeal by the main opposition Republican People's Party (CHP) for a re-run of the March 30 Ankara result on allegations of irregularities in the count.
A reversal of the Ankara result would be little more than a consolation prize for the opposition, which failed to dent Erdogan's support nationally in a vote that became a referendum on his rule as he battles allegations of corruption.
Erdogan dismisses the allegations as politically motivated.
A senior CHP official told Reuters its Ankara candidate would now take the case to the Constitutional Court, although Justice Minister Bekir Bozdag said on Tuesday any election board decision would be final.
"After what we've heard from the justice minister, I'm not very confident about the constitutional court. The European Court of Human Rights is the last and only option," a CHP adviser said.
No official results have been announced, but informal tallies from Turkish news channels put the Erdogan's AK Party at 45 percent nationwide, compared to 28 percent for the CHP.
In Ankara, incumbent mayor Melih Gokcek of the AKP secured 44.6 percent of the votes, narrowly beating CHP nominee Mansur Yavas on 43.8 percent.
Later on Wednesday the election board told vote organisers in the northwestern province of Yalova to investigate a complaint from AK Party that there has been irregularities there, Hurriyet newspaper reported.
AK lost that mayoral election to CHP, according to informal tallies of the result reported in the media. (Reporting by Gulsen Solaker and Jonny Hogg, additional reporting by Seda Sezer; Writing by Ece Toksabay; Editing by Nick Tattersall)