Papua New Guinea's Supreme Court has ruled that the election of Moresby North-East MP, Caspar Wollom, was null and void and a by-election must be held for the National Capital District electorate.
The court decision means there are now six vacant seats in Parliament, all waiting for by-elections to be held.
Mr Wollom lost his seat after the losing candidate, David Unagi, brought a case alleging that the returning officer had no discretion to count the votes in two ballot boxes which it was found had been interfered with.
Before the votes in the two boxes were counted, Mr Unagi was leading Mr Wollom by 744 votes.
The two boxes allegedly contained just under two thousand ballot papers but many were missing when the boxes were opened.