Pope Francis has called for a new focus on global hunger in a major address to delegates from the international Food and Agriculture Organisation in Rome.

In a hard-hitting speech, he warned against the tendency to "delegate" and "desert" in the face of the problem. He spoke of a "generic resignation" and "indifference" to hunger, as if it were unavoidable. "Sometimes one has the sensation that hunger is an unpopular topic, an insoluble problem," he said.

However, Francis argued that a lack of will was behind the continuing lack of food security in many parts of the world and said that it was possible to tackle the issue.

He instanced food speculation, responsible for high prices that hit the poor hardest. The products of the earth "have a value that we can say is 'sacred', given that they are the fruit of the daily work of persons, families, communities of farmers – a work that is often dominated by uncertainties, worries over climatic conditions, anxieties over the possible destruction of the harvest", he said.

He also spoke of the shocking waste of food – standing at around a third of everything produced globally – and said it was important to  reflect on the use of crops for biofuels and feeding animals: "It is worrying to know that a good quantity of agricultural products is used for other ends, perhaps good ends, but which are not the immediate need of one who is hungry."

Francis also warned against "monopolising of lands of cultivation by trans-national enterprises and states, which not only deprives farmers of an essential good, but which directly affects the sovereignty of countries". "There are already many regions in which the foods produced go to foreign countries and the local population is doubly impoverished, because it does not have food or land," he said.

"And what to say of the women who in many areas cannot possess the land they work, with an inequality of rights that impedes the serenity of family life, because the danger is run of losing the field from one moment to the other?" Most food production, he argued, was "in the main the work of family properties". He urged the FAO to support small-scale family enterprises through lobbying for better legislation.

The Pope urged a commitment to simpler lifestyles that would mean fewer resources were consumed, saying: "We must begin from our daily life if we want to change lifestyles, conscious that our little gestures can ensure sustainability and the future of the human family."

He concluded: "Let us modify our relation with the natural resources, the use of the soil, let us modify our consumption, without falling into the slavery of consumerism; let us eliminate waste and thus we will overcome hunger."

In another sign of the Pope's commitment to the poor, he is to open a homeless shelter on the edge of Vatican City in Rome. The shelter, which is still under construction, will host 30 people at a time and will be run by volunteers. It follows an earlier initiative to provide showers, haircuts and shaves under the colonnade of St Peter's Square.

Earlier this month Francis donated money to allow two busloads of poor people to travel from Rome to see the Shroud of Turin. He has also invited homeless people to a private viewing of the Vatican museums and the Sistine Chapel.