Plaid Cymru leader Adam Price will say no party has a “higher ambition for Wales” when its general election campaign is launched on Monday.
Mr Price is expected to tell the launch in Menai Bridge, Anglesey, that Wales is being “held back by Westminster”.
Plaid is aiming to increase its tally of four MPs won in 2017, with Ynys Mon a top target.
The party wants another referendum on Brexit in which it would campaign for the UK to remain in the EU.
In September, Mr Price called for his party to go into a snap poll promising to cancel Brexit without the need for a further referendum, but party members voted to support another vote on membership unless there is a prospect of a no-deal Brexit.