Pakatan Rakyat is confident of winning the Hulu Selangor by-election on April 25 although the contest is seen as close.
PAS deputy president Nasharuddin Mat Isa said going by history, the opposition not only had to face a political party, but also the entire government machinery during a by-election.
"At every by-election, we not only face UMNO as a party, but also the combined might of Barisan Nasional and the government machinery.
"It is not (a case of) a party competing with another party, but it is between a party and its political rival which has the backing of government institutions," said Nasharuddin, who is also PAS's election director for the Hulu Selangor by-election.
Nasharuddin hoped that the victories at recent parliamentary by-elections such as in Permatang Pauh, Kuala Terengganu and Bukit Gantang can be repeated, but added it was too early to predict the margin of victory in Hulu Selangor.
The Bachok MP however said Pakatan Rakyat's morale was high and it still enjoyed strong support in the constituency.