A lack of competition for top police officer roles is "deeply concerning", MPs have warned.
Police and crime commissioners (PCCs) have a duty to ensure there is a sufficient pool of candidates for chief constable vacancies, the Commons Home Affairs committee said.
It follows reports that there have been a number of recent chief constable recruitment exercises where there have been single or very few applicants.
The committee said: "It is deeply concerning that there have been so few applicants for recent chief constable vacancies, including in some of the largest and highest profile forces, such as Greater Manchester and West Midlands.
"It is also worrying that incumbent deputies often seem to be the only candidates."
Its report called for PCCs to ensure applicants for chief constable roles had served at least two years in another force at senior rank and recommended greater discretion to offer higher pay for the posts.
Labour MP Keith Vaz, the committee's chairman, said: "The pool of talent in policing is in danger of drying up, with so few applications for the most senior jobs in policing."
Greater Manchester PCC Tony Lloyd said: "At the outset I would like to say that Ian Hopkins was the right choice and an excellent chief constable to lead the coming years in Greater Manchester.
"The post was widely advertised and I made clear that this would be an open selection process from the very beginning.
"I did make clear to all institutions that could spread the word that this was an open process."
He added: "The select committee concludes that PCCs have a duty to ensure that there is a wide field of candidates and I agree that it is in the interest of society that the appointment of any senior police officer sees a range of candidates apply.
"When we appointed a deputy chief constable in GMP (Greater Manchester Police) there were four candidates for the job, three of whom were external and the external candidate came from outside of Greater Manchester Police."
The first elected PCCs took office in 2012 with a remit including appointing the chief constable and setting force budgets.
They represent 41 out of the 43 forces in England and Wales and the next group of commissioners will be selected at polls in May.
The report said any expansion of the PCC role should be "incremental and carefully judged".
It follows proposals that will allow the commissioners to take on responsibilities for fire and rescue services in their local area, while they are also set to play a greater role in the handling of complaints.
Last month Home Secretary Theresa May suggested they could play a role in the wider criminal justice system.
Mr Vaz said: "We should take care not to burden newly elected office-holders in May with too many additional responsibilities.
"They are already due to be given more powers for Fire and Rescue Services and Police Complaints, and an even broader remit on top of this may prove overwhelming and these proposals should be paused."