The former chairman of North Wales Police Authority has claimed policing in the area will worsen if a single, all-Wales police force is created.
North Wales Police has proposed more cooperation with Cheshire
Wrexham councillor Malcolm King attacked the idea at a meeting of the authority looking at reform proposals.
Authority members put forward the force's own idea of extending its co-operation with Cheshire Police.
The merger of Wales' four forces is one option put forward by Her Majesty's Inspectorate of Constabulary (HMIC).
Bringing all the forces - North Wales, South Wales, Dyfed-Powys and Gwent - together is one of three options being considered for Wales after Home Secretary Charles Clarke asked all police forces in Wales and England to look at the way they are organised.
The HMIC report, published in September, recommended mergers to create 30 larger forces.
Of the Welsh forces, only South Wales Police comes close to the preferred minimum size of 4,000 officers.
Other possibilities include merging the current four forces into two, or leaving things as they are.
At the North Wales Police Authority meeting at the force's headquarters in Colwyn Bay on Friday, Councillor King mounted a passionate defence of North Wales Police maintaining its independence.
Wales' four forces have appointed a team to look at reform plans
He said: "Policing will get worse in north Wales if we are joined up with a body which is much bigger, remote... we will lose control of our destiny, and people in north Wales will be much worse as a result.
"If you get into bed with a giant, when they roll over, you get squashed. Now the giant might be very apologetic about it afterwards and so on, but nevertheless you're squashed."
North Wales Police deputy chief constable Clive Wolfendale presented a report showing that by spending an extra £8m a year the force would be capable responding to serious crime and terror in the way required by the home secretary.
The police authority is to hold another meeting in a week's time.
The four Welsh police forces have appointed Paul Wood, deputy chief constable of South Wales Police, to assess the options for change.
He said a meeting would be held next week to determine which of the options under consideration - no change, two forces or a single force for Wales - would be presented to the home secretary.
The configurations of the two-force option could mean a merger of North Wales with Dyfed-Powys and South Wales with Gwent, or a merger of North Wales with Dyfed Powys and Gwent, with South Wales remaining as a stand-alone force.
Mr Wood said: ""We should not forget that we already have four high-performing police forces in Wales, with committed people and good links with our local communities.
"This project is about determining how that can be improved further."